technetium gives off gamma radiation.
The radiation emited is gamma ray
Radioactive
This depends on the amount, specific activity, chemical form, type of emitted radiations.
If it is related to Nuclear studies, then the answer would be fusion.
Thorium-232 is an alpha emitter; rarely decay by spontaneous fission or double beta decay are possible.
The radiation emited is gamma ray
Electromagnetic radiation in the form of thermal radiation is emitted as any substance, including iron, gets hot.
Alpha
???
Electromagnetic radiation in the form of thermal radiation is emitted as any substance, including iron, gets hot.
The radioactive decay of Phosphorus-32 emits only betaparticles (i.e. electrons) with a halflife of slightly longer than two weeks. No electromagnetic radiation at all is emitted.
gamma
In this case alpha particles are emitted.
Radioactive
Radioactive
Gamma radiation
Thorium is not a radiation but a chemical element, metal, natural and radioactive.